A tailbox is what its name implies- a rigid box that sits behind the rider, usually
intended for carrying cargo. As a side benefit, it can improve the aerodynamics
of the bike slightly.

I was inspired to use Coroplast by Bill Volk and his Coroplast Craziness page
and Ed Gin's Fairing
Seminar. What I discovered is that Coroplast is an incredibly easy material
to work with- it's cheap, easy to cut, tough to goof up, waterproof, easy to
clean, and available. Since it's commonly use for outdoor signs, most sign
making shops will have it in stock. If you're really cheap, wait until the next
election and volunteer to clean up candidates' signs afterwards. This usually
yields many useful large pieces at no cost. You can use these for interior
panels (like I did) or, if you don't mind the printing or the colors, on
exterior panels.

The one deficiency of Coroplast is that it can't be glued easily.
Epoxy, silicone, hot glue, and rubber cement have been tried with varying
success. Coroplast's Website has some good information on what works and
what doesn't: Bonding
and Adhesion of Coroplast. Since the tailbox's parts move and vibrate, most
bonding methods will fail in short order. My building method is to stitch
the edges together with plastic zip ties. These are cheap, easy to find,
and strong but not particularly elegant.

The dimensions on the following pages will allow you to build a similar
tailbox. It's designed to fit a Lightning P-38 with a rear rack. In fact, I
built the original simply by eyeballing most of the pieces- I didn't have any
detailed dimensioned drawings before starting. The curved sides give it
rigidity and keep it pretty quiet. With some thought and ingenuity, it could be
adapted to most recumbent designs. Heck, with a little reworking, it
could fit an upright bike!